Translocation Associated Membrane Protein 1 Contributes to Chronic Constriction Injury-Induced Neuropathic Pain in the Dorsal Root Ganglion and Spinal Cord in Rats

Neuropathic pain is a severe debilitating state caused by injury or dysfunction of somatosensory nervous system, and the clinical treatment is still challenging. Translocation associated membrane protein 1 (TRAM1), an adapter protein, participates in a variety of transduction pathways and mediates the biological functions such as cell proliferation, activation, and differentiation. However, whether TRAM1 is involved in the pathogenesis of neuropathic pain is still unclear. In our study, we reported the role of TRAM1 in the maintenance of neuropathic pain induced by chronic constriction injury (CCI) on rats. By western blot and staining, we found that TRAM1 increased in the dorsal root ganglion (DRG) neurons and spinal cord (SC) neurons after CCI. Being similar to IB4-, CGRP-positive expressed area, TRAM1 also expressed in the superficial laminae of the spinal cord dorsal horn (SCDH), suggesting it was related to the innervations of the primary afferents. Moreover, intrathecal injection of TRAM1 siRNA or Toll-like receptor 4 (TLR4) inhibitor induced low expression of TRAM1 in SC, which alleviated the pain response induced by CCI. The upregulation of p-NF-κB expression was reversed by TRAM1 siRNA in SC and DRG, and intrathecal injection of p-NF-κB inhibitor relieved neuropathic pain. All the data indicated that TRAM1 could take part in CCI-induced pain and might be a potential treatment for chronic neuropathic pain.